The Force: Due to The Stranger's connection to the Force, he was extremely powerful.
Telekinesis: The Stranger could telekinetically move objects or other individuals, without physically touching them.
Force Push: The Stranger can telekinetically send him opponents flying through the air, causing serious injury or temporarily incapacitating/knocking them unconscious, depending on how much power is unleashed.
Force Pull: The Stranger can telekinetically pull his opponents or objects towards him.
Force Choke: The Stranger can telekinetically choke his opponents to either weaken, kill or intimidate them.
Force Grip: The Stranger can telekinetically lift his opponents off the ground and into the air, sometimes by the neck, to immobilize them.
Saber Throw: The Stranger can telekinetically guide his lightsaber towards his opponents and return the weapon back to his hand, similar to a boomerang or shuriken.
Force Levitation: The Stranger can telekinetically float down from on high areas or slow down his fall to the ground.
Telepathy: The Stranger can telepathically communicate with other individuals over small or vast distances. Additionally, The Stranger's telepathy was so advance that Yord alluded to feeling him infiltrate his mind, which is what he did to the other Jedi while during a battle. He undermines the target's confidence and possibly weakens their focus, thus reducing their overall efficacy in duels.
Mind Probe: The Stranger could sense and sift through the thoughts of other sentient beings.
Memory rub: the Stranger can completely erase memories.
Force Stealth: The Stranger is able to hide his Force Sensitive nature, as well as prevent the detection of his powers. This veil ends during combat, however. Yet, even in battle, the true depths of his powers were only vaguely sensed, without knowing their full extent. It is also isn't clear if he used the Force to accomplish this, however, he was capable of vanishing from enemies, if they were even just momentarily distracted. He can remain hidden until he chooses to reveal himself again.
Force Sense: The Stranger could sense other sentient beings' emotions, the future, ripples in the Force caused by momentous or traumatic events, impending danger, and the presence of other light or dark side Force-users.
Force Jump: The Stranger could jump or leap at great distances.
Abilities
Master Lightsaber Duelist: The Stranger was is a highly skilled lightsaber duelist. He manage to take on eight Jedi an kill nearly all of them was also one of the most deadliest lightsaber dualists in galactic history.
Form I: The Stranger is very skilled in Shii-Cho.
Form II: The Stranger is very skilled in Makashi.
Form III: The Stranger is very skilled in Soresu.
Form IV: The Stranger is highly skilled in Ataru.
Form V: The Stranger is very skilled in Shien/Djem
Form VI: The Stranger is highly skilled in Niman.
Form VII: The Stranger is extremely skilled in Juyo.
Jar'Kai: The Stranger is highly skilled in Jar'Kai.
Tràkata: The Stranger is highly skilled in Tràkata.
Expert Hand-To-Hand Combatant: The Stranger is a highly skilled hand-to-hand combatant, even incorporating it in his lightsaber sequence and holding his own against Sol, although only for a short time.
Expert Pilot: The Stranger was highly skilled in piloting most other speeders and most other different types of flying crafts.
Weapons and Equipment
Lightsaber
Lightsaber: The Stranger has a red-bladed lightsaber. The saber is a unique split saber that has a smaller shoto lightsaber on the bottom.
Cortosis Armor: The Stranger wore a helmet and arm brace forged mostly out of cortosis, a rare material that can short out a lightsaber blade.
Exile II: The Stranger piloted a starship called Exile II. The ship was used by Mae a few times.